The customers, the passengers, the people who actually get the trains every day, packed like cattle into the carriages, forced to put up with daily delays and cancellations … they weren't too happy, of course – passenger focus groups were mobilised, sporadic protests popped up at odd stations across the country – but FirstGroup won't be too bothered about any of that.

And I should know. I commute every day between Oxford and London, on the line operated by First Great Western. It is not an enjoyable experience. My trains rarely often arrive late, I hardly ever get a seat. And it costs me nearly £500 a month.

Cost is the central issue. As a commuter you're a captive market – you can't choose not to go to work. And what really rankles about shelling out above inflation fare hikes is that the service does not seem to show a corresponding improvement.

For a while, I put up with it like everyone else, doing that peculiarly British thing of internalising all the frustration, getting furious and remaining silent. And then, one morning in June last year, something snapped – and so I did that other peculiarly British thing, and wrote a letter of complaint.

Except my letter had a twist. I found the email address of the managing director (surprisingly difficult, given it doesn't appear anywhere on the website) and I composed a letter expressly designed to waste as much of his time that day as he had wasted of mine. And then I promised that I would write again every single other time I was delayed. The length of each letter would correspond to the length of that day's delay, at a rate of 100 words per minute: an extra five-minutes in the morning would mean a pithy 500 word missive – but a 25-minute hold-up meant a 2,500 word epic.

Extraordinarily, the managing director wrote back. And so started a correspondence that lasted nine months, 98 letters, more than 24 hours' worth of delays and around 100,000 words. By letter three or four, of course, I'd pretty much run out of things to say – and so I started taking the mickey. If protesting wasn't going to improve the service, I thought I might be able to humiliate him into action.

My blog became an evolving illustration of how shoddy a service FirstGroup were providing with their First Great Western division. I averaged three letters a week – that's three journeys out of every 10 delayed, or 30%. And yet the company itself claims to have far more impressive figures – an 85% punctuality rate and 93% reliability. How could that be?

It turns out that according to the "official" way of measuring things, a delay of five minutes or less doesn't actually count as a delay at all. And that a train's arrival time is measured on a point just outside the station – as opposed to the actual time it comes to a stop. Theoretically, a train could wait for hours between that point and the platform and still be "on time".

Reliability figures are even more obtuse. A train is only deemed unreliable if it fails to turn up. So long as it eventually arrives, no matter how late, it's officially "reliable".

This the kind of corporate spin and doublespeak I dealt with during the time that I was writing to them – despite the almost daily evidence in my letters that the service they were providing was anything but reliable, or punctual, or even satisfactory.

Naturally I raged against this sophistry in my letters to the managing director – and to be fair to him, his replies were always courteous and apologetic … if a little too eager to lay most of the blame with Network Rail.

So in the end there was little left to do but ridicule him – and the contemptuous way his company treats its customers. You're never going to beat the playground bully with force, or expose the bigot with reason – but you can at least make them look silly with humour.

As Mark Twain said: "the human race has only one effective weapon and that is laughter". And if you can't beat them – at least make them look silly.